/*
 * include/nuster/dict.h
 * This file defines everything related to nuster dict.
 *
 * Copyright (C) Jiang Wenyuan, < koubunen AT gmail DOT com >
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation, version 2.1
 * exclusively.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
 */

#ifndef _NUSTER_DICT_H
#define _NUSTER_DICT_H

#include <nuster/common.h>
#include <nuster/http.h>
#include <nuster/key.h>


enum {
    NST_DICT_ENTRY_STATE_INIT      = 0,
    NST_DICT_ENTRY_STATE_VALID,
    NST_DICT_ENTRY_STATE_REFRESH,
    NST_DICT_ENTRY_STATE_UPDATE,
    NST_DICT_ENTRY_STATE_STALE,
    NST_DICT_ENTRY_STATE_INVALID,
};

/*
 * A nst_dict_entry is an entry in nst_dict hash table
 */
typedef struct nst_dict_entry {
    struct nst_dict_entry      *next;

    int                         state;

    nst_key_t                   key;

    hpx_buffer_t                buf;

    hpx_ist_t                   host;
    hpx_ist_t                   path;
    hpx_ist_t                   etag;
    hpx_ist_t                   last_modified;

    int                         header_len;
    uint64_t                    payload_len;

    uint64_t                    expire;
    uint64_t                    ctime;
    uint64_t                    atime;

    nst_rule_prop_t             prop;

    /* see rule.extend */
    uint64_t                    access[4];

    /* extended count  */
    int                         extended;

    struct {
        struct {
            nst_memory_obj_t   *obj;
            nst_memory_item_t  *item;
        } memory;
        struct {
            char               *file;
        } disk;
    } store;
} nst_dict_entry_t;

typedef struct nst_dict {
    nst_shmem_t                *shmem;

    nst_dict_entry_t          **entry;
    uint64_t                    size;           /* number of entries */
    uint64_t                    used;           /* number of used entries */

    uint64_t                    cleanup_idx;

    uint64_t                    sync_idx;

    nst_store_t                *store;

#if defined NUSTER_USE_PTHREAD || defined USE_PTHREAD_PSHARED
    pthread_mutex_t             mutex;
#else
    unsigned int                waiters;
#endif
} nst_dict_t;


static inline int
nst_dict_entry_expired(nst_dict_entry_t *entry) {

    if(entry->expire == 0) {
        return 0;
    } else {
        return entry->expire <= nst_time_now_ms() / 1000;
    }

}

static inline int
nst_dict_entry_stale_valid(nst_dict_entry_t *entry) {
    return entry->expire + entry->prop.stale > nst_time_now_ms() / 1000;
}

static inline int
nst_dict_entry_inactive(nst_dict_entry_t *entry) {

    if(entry->prop.inactive == 0) {
        return 0;
    } else {
        return nst_time_now_ms() - entry->atime > entry->prop.inactive * 1000;
    }
}

static inline int
nst_dict_entry_invalid(nst_dict_entry_t *entry) {

    /* check state */
    if(entry->state == NST_DICT_ENTRY_STATE_INVALID) {
        return 1;
    }

    /* check expire */
    if(entry->state == NST_DICT_ENTRY_STATE_VALID) {

        if(nst_dict_entry_expired(entry)) {
            return 1;
        } else {
            return nst_dict_entry_inactive(entry);
        }
    }

    /* check stale */
    if(entry->state == NST_DICT_ENTRY_STATE_STALE) {
        return !nst_dict_entry_stale_valid(entry);
    }

    return 0;
}

static inline int
nst_dict_entry_valid(nst_dict_entry_t *entry) {

    if(entry->state == NST_DICT_ENTRY_STATE_VALID) {
        return !nst_dict_entry_expired(entry);
    }

    return 0;
}

int nst_dict_init(nst_dict_t *dict, nst_store_t *store, nst_shmem_t *shmem, uint64_t dict_size);
void nst_dict_cleanup(nst_dict_t *dict);

nst_dict_entry_t *nst_dict_get(nst_dict_t *dict, nst_key_t *key);
nst_dict_entry_t *nst_dict_set(nst_dict_t *dict, nst_key_t *key, nst_http_txn_t *txn,
        nst_rule_prop_t *prop);

int nst_dict_set_from_disk(nst_dict_t *dict, hpx_buffer_t *buf, nst_key_t *key, nst_http_txn_t *txn,
        nst_rule_prop_t *prop, char *file, uint64_t expire);

void nst_dict_record_access(nst_dict_entry_t *entry);

#endif /* _NUSTER_DICT_H */